I brought a bleed kit off ebay (total bleed solutions - others like epic are available).

The HS11 have an EBT plug (not a threaded screw like more expensive siblings). This is a bit fiddly to remove and this plug turn out to be the cause of my issue.

After fitting all the syringes I could not push the caliper syringe in, it was like the system was still closed. Eventually as I push harder and harder the pressure built up and the plastic hose came off the syringe.

It did not make sense, so I unscrewed the lever hydraulic hose to see if the oil would flow out when I pushed the syringe in, which of course it did. Quite messy make sure you have plenty of paper towels and alcohol spray.

When looking at the fitting on the lever hose I checked the length against the lever body and EBT port and realised that it was blocking the EBT port when fully tightened. So I added an O-ring for luck and loosely re-fitted the hydraulic hose to the lever.

The bleed process then worked fine, just as in the video, the oil was pushed up in to the lever syringe.

I tightened the hydraulic hose up (8mm fitting) after removing the syringes.

For those who think that Magura rim brakes do not need bleeding, the fresh royal blood is clear sky blue, the flushed old stuff was black as soot.

That's very weird. I've worked on many hydraulic brakes of every brand and I've never seen anything other than clean fluid. The system is closed, so there should be no chance of any contamination. There must be something else wrong with your bike unless a previous owner decided to use old engine oil because they ran out of brake fluid.

With disc brakes, you can understand the possibility of burning, though still pretty unlikely, but the piston on rim brakes is a long way from any heat.